The KAP Legend System is a modern, flexible legend design standard used for mechanical keyboard keycaps, created by designer kapowaz and engineered/manufactured in collaboration with Keyreative.
Keyreative can use a ‘hybrid’ dye-sub/injection moulding technique (illustrated in the cutaway image below).

An initial shot of white PBT is first used to create the legends, before colours are added using a dyesub technique. Finally, the outer keycap is moulded as a second shot.
This allows using a much wider variety of colours on a single keycap (as with dye-sub), but with the crisp legends of doubleshot moulding.